Structural preservative.



UNITED STATES PATENT OFFICE.

Specification of Letters Patent.

Application filed March 20, 1905. Serial No. 251.172.

Patented June 12,1906.

To all whom it may concern: a

Be it known that I, Gnonen D. COLEMAN, a citizen of the United States, residing at Brookline, in the county of Norfolk and State of Massachusetts, have invented certain new and useful Improvements in Structural Preservatives; and I do hereby declare the tains to make and use the same.

followingto be a full, clear, and exact de scription of the invention, such as will enable others skilled in the art to which it apper- The present invention relates to an improvement in structural preservatives.

Much difficulty has been experienced in securing an efficient protective coating for such steel structural work as bridges, iers, lighthouses, train-sheds, and the like, an particularly in the last named, in which the sulfurous-acid gases promote the oxidization of the structure.

The object of the present invention is to produce a coatin for structural work which will be capable 0? being securely attached to the surface of the structure and which at the same time will present a surface of weather and gas resistant quality.

To this end the present iIlVelltlOll consists in the coating herelnafter described, and particularly defined in the claims.

The surface of the structure to be coated will first be cleaned, and if old and rusty the cleaning is best done by the use of a sandblast, and then to the surface of the structure thus cleaned is applied a layer of slowdryintgaintas, for example, a paint made of re l dad and raw linseed-oil in which no drier is used-the result being a resilient and elastic but dense layer which will securely attach itself to the sm'face of the structure irrespective of its irregularities and whichwill not break or crack with the come and o of the parts thereof. While thislayer of pamtis still moist and tacky the surface isspra ed with comminuted lead or sharp sand. e particles of this layer partially embed themselves in the layer of paint and by reason of their irregularities securely affix themselves thereto. The paint above referred to is sufficiently dense and tough to carry the layer of lead or sand and to hold it firmly in place. Upon the surface of the coating as thus apphed is sprayed a coating of ydraulic or,

preferably, Portland cement about the consistency of cream, which enters the interstices between the particles of leader sand, and is thus anchored to the surface thereof and afiords when it hardens asurface substantially of stone, which will afford an efficient lnjurious gases.

The intermediate layer, which has been referred to as a layer of lead or sand comprises an anchoring layer, which by reason of the irregular surface of the particles thereof anprotection against the attacks of weather and chors the cement coating to the aint layer.

This layer may be of any suitab e material, lead being preferred because of its quality of becoming passlve under the influence of the atmos here wherever the surface of the cement 1s disturbed; but in the broader aspects of the invention it is considered that any suitable granular material is within the contemplation of the invention for use as the anchoring layer.

Havin thus described the invention, what is claime is 1. A structural preservative consisting of a layer of slow-drying paint ap lied to the surface of the structure,-an anc oring layer of granulated material embedded in but proi'ecting from the surface of the paint, and a ayer of hydraulic cement secured to and covering the anchoring layer, substantially as described.

2. A structural preservative, consist of a layer of slow-drying paint ap lied to the surface of the structure, an anchoring layer of comminuted lead, and a layer of Portland cement applied to the anchoring layer of lead, substantiall as described.

3. A structura preservative consisting of a layer of oil-paint applied to the surface of the structure, an anchoring layer of granulated material embedded in but projecting from the surface of the paint, and a layer of cement secured to and cover' the anchor- 1 m layer, substanially as descm ed.

s testimony whereof I affix my signature inpresence of two witnesses.

GEORGE D. COLEMAN 

